The present invention relates generally to a boat propeller, and more particularly to a boat propeller which can be easily changed in its pitch.
The propeller pitch refers to an angle formed between a blade chord line in any radial position and a plane of rotation. In other words, the propeller pitch refers to an inclination of the propeller blade surface. The blade angle determines the performance of the propeller. Accordingly, the propellers are made to be different in pitch, depending on the type and the purpose of the propellers.
The propellers were used to be made integrally. As a result, various molding tools were used to make the propellers different in pitch, thereby resulting in the high cost of producing the propellers.
The boat propeller pitch affects the cruising speed, the thrust, and the fuel efficiency of the boat. For this reason, the small boat is provided by its operator with a propeller with an appropriate pitch on the basis of the journey data, such as the time of the journey, the carrying load, the fuel remaining in the tank, and the like. Nowadays, there are boat propellers with an adjustable pitch. As a result, the boat operators do not have to purchase a variety of boat propellers different in pitch. However, such conventional boat propellers with the adjustable pitch are complicated in construction and operation and are not cost-effective.
The primary objective of the present invention is to provide a cost-effective boat propeller adjustable in pitch.
It is another objective of the present invention to provide a boat propeller which can be adjusted in pitch in a short notice to meet the requirements of journey.
It is still another objective of the present invention to provide a boat propeller which is simple in construction, cost-effective, and adjustable in pitch easily.
The boat propeller of the present invention comprises a hub, a plurality of angle setting members and blades. The hub is formed of two cylindrical members, which are detachably fastened together in an end-to-end manner and are provided in the junction with a plurality of receiving cavities. The angle setting members are removably disposed in the cavities and are located by a retaining portion which is inserted into the hub. The angle setting members are provided with a connection portion. The blades are mounted around the periphery of the hub such that the inner ends of the blades are inserted into the cavities, and that the inner ends of the blades are located by the connection portions of the angle setting members. The angular relationship between the retaining portions and the connection portions determines indirectly the blade angle in relation to the hub. Various blade angles can be thus provided by the angle setting members of various shapes.